1. Field of the Invention
The present invention relates to an image display apparatus, and more particularly to an image display apparatus having a potential introducing terminal. The invention also relates to an information display apparatus such as a television using the image display apparatus.
2. Related Background Art
An anode cap of an image display apparatus such as a CRT is a structural component for connecting a high voltage cable to an anode button of a CRT. A conventional anode cap has the structure that a metal body is covered with an insulating cover (Refer for example to Japanese Patent Publication No. 56-21231, Japanese Patent Application Laid-open Nos. 10-64456, and 2000-251981).
FIG. 10 is a cross sectional view showing a mount state of a conventional anode cap on an outer wall of a CRT. Referring to FIG. 10, reference numeral 41 represents a high voltage lead wire, reference numeral 42 represents a metal body, reference numeral 43 represents a contact piece, reference numeral 44 represents an insulating cover, reference numeral 45 represents a high voltage lead wire holder portion, reference numeral 46 represents a bowl portion, reference numeral 47 represents an anode cup, and reference numeral 48 represents an outer wall of CRT. The contact piece 43 fixed to the metal body 42 is provided at the front end of the high voltage lead wire 41. This contact piece 43 is electrically connected to a core wire of the high voltage lead wire 41.
The insulating cover 44 has the bowl portion 46 and the high voltage lead wire holder portion 45 which accommodates and holds the high voltage lead wire 41 at the position where the contact piece 43 is coupled. A through hole for the contact piece 43 is formed at the bottom of the bowl portion 46. The contact piece 43 is made of a bent linear conductor having an elasticity. Two contact pieces 43 are extend in the bowl portion 46. The insulating cover 44 is made of elastic material such as silicon rubber.
The outer wall 48 of CRT is generally made of glass. The inner surface of the outer wall 48 is formed with an anode conductive film (not shown). The anode conductive film and the bottom of the anode cup 47 is in contact with each other. The bowl portion 46 widely covers the connection area between the contact piece 43 and anode cup 47 to ensure insulating protection.
As described above, the conventional anode cap has the structure that the metal body is covered with the insulating cover. A distance between the border of the insulating cover and the metal body has been set to a distance sufficient for preventing creeping discharge when a high voltage is applied. There is therefore less necessity for adopting a special process or structure for preventing creeping discharge with nearby components.
Irregular projections have been invented as the means for improving a dielectric breakdown voltage between two conductors (refer for example to Japanese Patent Application Laid-open Nos. 05-006748, 06-052812 and 07-131125). The means for improving a dielectric breakdown voltage by using the irregular projections disclosed in these applications can be applied to a high voltage applying portion of an image display apparatus when the present invention is reduced in practice.